This disclosure relates to repairing gas turbine engine components and, more particularly, to determining a location of an elevated stress region of a gas turbine engine component.
Gas turbine engine components, such as turbine blades, turbine vanes, compressor blades, compressor vanes, or other components typically operate in a relatively high stress and high temperature environment. The stresses and temperature may result in damage to the component from corrosion, erosion, deformation, or the like. Depending on the type and severity of the damage, the components may be repaired and reused.
The type of repair process depends on the type of damage. For example, relatively elevated stresses and temperatures within the engine may cause deformation of a blade, vane, or other component. For a blade that is effectively cantilevered from one end, the thermal and mechanical loads may result in a twisting deformation of the blade about its axis. The blade may be restored to near its original shape by twisting the blade in the opposite direction that caused the deformation. Other stresses may cause bending or other types of deformation.
Typically, after a repair process, one or more representative components are metallurgically analyzed to determine whether the stresses applied during the repair process damaged the component. For example, if the stress exceeds the yield strength of the component, cracks may form. A typical metallurgical analysis requires that the representative component be sectioned into a relatively large number of pieces. The pieces are then analyzed through known metallurgical methods for cracking or other damage.
To reduce the number of sections that are required, it is desirable to predict a location of a region of highest stress on the component using computer analysis and then sectioning only that region. This would provide analysis of the region of the component that is most vulnerable to cracking. However, one possible drawback of using computer analysis is that it is based on simulation, modeling, and experimental data that may deviate from actual conditions and lead to an inaccurate prediction of the location of the highest stress region.
Additionally, the computer analysis may be used to determine a maximum amount of stress that can be applied to a component during a repair process without causing cracking. However, since the computer analysis results can deviate from actual conditions that cause cracking, the stress used in the repair process may not be reliable for avoiding cracking.
Accordingly, there is a need for a method to verify that a predicted location of a high stress region on a gas turbine engine component is accurate and to accurately determine a maximum amount of stress that can be used in the repair process without causing cracking.